| The sources of natural products include animals,plants and microorganisms.Plants and microorganisms can produce a variety of natural products.Natural products have a wide range of applications.They can effectively prevent infectious diseases,inhibit or kill bacteria,viruses,fungi and tumors.Their remarkable physiological activities and molecular structures with novel structures have attracted the attention of numerous chemical and pharmaceutical researchers for a long time.Therefore,in order to find compounds with novel structures and significant biological activities from medicinal plants and their rhizosphere soil,this paper selected ligularia narynensis plants and their rhizosphere bacteria collected in Xinjiang as the research objects.Firstly,ligularia narynensis was taken as the research object.The extracts were obtained by soaking the roots,stems and leaves of plants in methanol,extracting them with ethyl acetate,petroleum ether and n-butanol respectively,and concentrating them under reduced pressure to obtain ethyl acetate extracts.The ethyl acetate fractions were decolorized and segmented by using macroporous resin column chromatography.The chemical components were separated by using conventional column chromatography,preparative thin layer chromatography and recrystallization,The structures of most of the compounds were determined by using various modern spectral techniques(IR、UV、1H NMR、13C NMR、1H-1H COSY、NOESY、HSQC、HMBC,etc.)and appropriate chemical transformation methods.Twenty compounds,mainly terpenes,were identified,four new compounds.Secondly,three soil samples were collected from the rhizosphere soil of ligularia narynensis by biological separation and purification method,and 20 strains of bacteria were isolated and purified.Through screening of pathogenic fungi activity,a strain of biocontrol bacteria QF-2 was found,which had a very significant inhibitory effect on pathogenic fungi.Gene sequencing and anti-SMASH analysis of strain QF-2 showed that the gene cluster contained 21 gene clusters,which was identified as Bacillus,Therefore,QF-2 was identified as the target bacteria.The secondary metabolites of the strain were studied.Five compounds were isolated by various modern separation technologies and means.Because the strain has good antifungal activity,the strain was fermented in large quantities in order to find compounds with novel structure and good antibacterial activity.Finally,this study further enriched the chemical constituents of sesquiterpenes in natural products,which is helpful for pharmacologists to study the structure-activity relationship,and provides a reference for further study of the chemical constituents of ligularia narynensis and rhizosphere bacteria. |
